Developing microfabrication methods and optimal structures for diamond-based cooling structures

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K14163
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 18020:Manufacturing and production engineering-related
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Matsumae Takashi 国立研究開発法人産業技術総合研究所, エレクトロニクス・製造領域, 主任研究員 (10807431)
• Project Period (FY): 2022-04-01 – 2024-03-31
• Keywords: 微細加工 / ダイヤモンド / ニッケル / ナノインプリント

Outline of Final Research Achievements

Ni has a higher solubility limit for carbon and is less likely to form carbides. In this study, we demonstrated that micro-patterns can be fabricated by pressing a Ni mold for nano-imprinting onto a diamond substrate at high temperatures. This process enables fin structures with a width of 0.005-0.050 mm and a depth of 0.002 mm on the diamond substrate. Then, a graphite layer was generated at the Ni/diamond interface after cooling to room temperature. This layer can be exfoliated by heating to 1000°C because of thermal stress. This can contribute to the repeatable use of the expensive Ni micro molds. In addition, a diamond substrate having a 0.001-mm-thick boron-doped conductive layer at a concentration of 2E16/cm3 was used to reduce a 50 Hz AC magnetic field. However, there is no significant difference between diamond substrates with and without the boron-doped layer. The sufficient reduction may require an increase in boron concentration and film thickness.

Free Research Field

微細加工

Academic Significance and Societal Importance of the Research Achievements

ダイヤモンドは固体物質中最大の熱伝導率をはじめとして、電気・化学・機械的に特異な物性を持っている。そのため既存デバイスと複合化する高機能冷却構造や、パワー・量子・センシング・耐放射線など次世代デバイス応用が期待されている。これらデバイスの製造にはフィンなどの微細構造をダイヤモンド表面に加工する必要があるが、ダイヤモンドは非常に高い硬度をもち機械加工が困難で、また化学的にも安定でエッチングが難しい。今回Ni/ダイヤモンド間の高温での固溶現象が明らかになり、また簡易なダイヤモンドの微細加工が開発されたことで、ダイヤモンドを用いた冷却構造や次世代デバイスへの貢献が見込める。